AT&T Brand Guidelines at a Glance 4 The alternate signature has a larger AT&T logotype and is used only when visibility is limited or reproduction methods are restricted, such as signage or sponsorship logos. The alternate signature is available only upon request from Brand Management. The out of home (OOH) signature is reserved for large formats on external applications such as billboards. The OOH signature uses a larger type for better visibility. Restricted Uses There are two other versions of the AT&T signature, used only in select cases. When in doubt, use the preferred signature. When using these signatures, follow the same clear space, color and design system guidelines as those for the AT&T signatures.